Lameness examination of the horse

Question 1

What is the definition of lameness

Answer 1

A clinical sign or manifestation of signs of inflammation, pain, neurological disease, or mechanical defect that result in a gait abnormality characterized by limping

Question 2

What is the most common cause of lameness (general)

Answer 2

Pain (neuro disease and mechanical issues also important causes)

Question 3

What is the aetiology of lameness

Answer 3

-Abnormal stress on normal bone or cartilage: stress may be direct, severe trauma, or repetitive trauma
-Normal stress on abnormal bone or cartilage: may be abnormal because of a developmental disease (OCD or ALD)

Question 4

What are the stages of a lameness exam

Answer 4

-History
-Physical exam
-Evaluate gait
-Determine site of lameness: physical exam, flexion tests, diagnostic anesthetia
-Imaging
-Other tests

Question 5

What should you establish in during the history section of the exam

Answer 5

-Establish age
-Establish specific use of horse
-Establish onset, duration, progression, and clinical signs of the lameness
- Establish past and current levels of training, previous injury, and response to treatment of current lameness

Question 6

What is normal and uncommon in terms of a horse resting its limbs

Answer 6

-Resting on rear limb and alternating occassionally is normal and common
-Resting a forelimb is uncommon and usually a red flag

Question 7

What location of lameness causes muscle wasting in the hips vs in the forearm/shoulder

Answer 7

-Hips: chronic lameness in the stifle or higher
-Forearms/shoulder: chronic lameness anywhere in forelimb

Question 8

How long does lameness have to go on for for muscle atrophy to be seen

Answer 8

Minimum of two weeks

Question 9

Will chronic forelimb lameness cause the foot of the lame forelimb to be bigger or smaller

Answer 9

Smaller

Question 10

What is meant by gait and beat

Answer 10

Gait: manner of walking or stepping
Beat: number of foot strikes in a single stride cycle

Question 11

What is meant by step and stride

Answer 11

Step: distance between footprints of the 2 front feet or 2 back feet
Stride: distance between consecutive footprints of the same foot (A stride covers twice the distance of a step)

Question 12

What are the 5 phases of a horses stride

Answer 12

1)Landing: foot hits the ground and limb begins to receive impact of the body’s weight
2)Loading: the body moves forward and the horse’s center of gravity passes over the hoof (fetlock descends to its lowest point)
3)Stance: fetlock and pastern rise as the horse’s center of gravity moves ahead of the foot. Limb begins to push off the ground. Transition from loading phase to stance phase stresses the limb, flexor apparatus lifts horse’s weight
4)Breakover: time the heels leave the ground to the time the toe leaves the ground. Heels lift, foot begins to pivot at toes, and foot begins to leave the ground. At the same time, knee or hock begins to flex
5)Swing: limb moves through the air and straightens in preparation for landing

Question 13

What are the cranial and caudal phases of the stride

Answer 13

Cranial phase: length of stride of one limb cranial to stance phase of the contralateral limb
Caudal phase: length of stride caudal to stance phase of the contralateral limb

Question 14

What is supporting limb lameness and swinging limb lameness

Answer 14

Supporting limb lameness: lameness that is painful during the weight-bearing phase of the stride (most lamenesses are this type)
Swinging limb lameness: lameness that primarily affects the way the horse carries the lame limb (reserved for mechanical defects of gait, such as fibrotic myopathy, upward fixation of the patella and stringhalt)

Question 15

How does a horse’s head/neck move when it is lame

Answer 15

-When the sound limb hits the ground, the horse lowers its neck in relief. When the lame limb hits the ground, the horse lifts it’s head in attempt to alleviate some of the pain and pressure on the leg

Question 16

What are some other details of the forelimb that can help you identify lameness

Answer 16

-Fetlock of the sound limb drops further than that of the lame limb
-Heel of foot should contact ——-ground first, pain in heel may cause horse to land on toe first
-Cranial phase of lame limb often reduced
-Arc of flight of lame limb may be reduced/ may cause horse to drag toe

Question 17

What extra things can you look for to identify a hindlimb lameness

Answer 17

-Observe tuber coxae, lame limb has a greater rise and fall than the sound limb
-Markers placed on tuber coxae may make asymmetry of motion more apparent

Question 18

What are the grades on the AAEP scoring system for grading lameness

Answer 18

0) No lameness
1) Lameness difficult to detect and inconsistent
2) Lameness difficult to detect but consistent under certain conditions
3) Lameness can be seen consistently in trot in straight line
4) Lameness is obvious at the walk
5) Reluctant to bear weight/ minimal weight-bearing in motion and/or at rest

Question 19

How do we evaluate gate

Answer 19

Subjective 0 to 10 scale
0 is sound, 1 is barely perceptible lameness, 10 is inability to bear weight on lame limb

Question 20

Why do we do flexion tests

Answer 20

-They can exacerbate a subtle lameness
-We can attempt to differentiate if lameness is associated with distal or proximal portion of limb
-We grade the change in the lameness after flexion, not lameness itself (no response, mild, moderate, marked)

Question 21

What are the types of wedge type and what do they do

Answer 21

-Heel and toe wedge
-Heel: Reduced stress of DDFT, increased stress on SDFT/suspensory ligament
-Toe: Increased stress on DDFT, navicular bone, associated ligaments, and bursa

Question 22

What is the Churchill test

Answer 22

-Tests for distal tarsal pain
-Digital pressure applied to the inside head of the splint bone (MT2 and fused first and second tarsal bones)

Question 23

Why do we use diagnostic anesthesia and which methods do we use

Answer 23

-Anatomical site of lameness is localized by diagnostic analgesia
-Methods are: perineural anesthesia, intrasynovial anesthesia, and direct infiltration over suspect superficial lesions